The Blue Danube is the common English title of An der schönen blauen Donau op. 314 (On the Beautiful Blue Danube), a waltz by Johann Strauss II, composed in 1866. The sentimental Viennese connotations of the piece have made it into a sort of unofficial Austrian national anthem. It is a traditional encore piece at the annual Vienna New Year's Concert.The Blue Danube was used in the film 2001: A Space Odyssey.